Stable nitroxide radicals from 2-substituted quinoline-N-oxides with organometallic compounds

Stable nitroxide radicals were obtained by the oxidation of 1-hydroxy-2,2-diphenylquinolines prepared by allowing the PhMgBr to act upon a number of 2-phenylquinoline-N-oxides in THF. Methyl-, ethyl- and benzyl-magnesium compounds gave rise to other nitroxides which were identified from their ESR spectra, but not isolated in the solid state. t-Butyl-magnesium chloride reacted with quinoline-N-oxides giving only the deoxidation products. The ESR spectra of numerous nitroxide radicals were interperted and discussed.